diff options
| -rw-r--r-- | drivers/gnss/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/gnss/Makefile | 3 | ||||
| -rw-r--r-- | drivers/gnss/usb.c | 213 |
3 files changed, 227 insertions, 0 deletions
diff --git a/drivers/gnss/Kconfig b/drivers/gnss/Kconfig index bd12e3d57baa..d7fe265c2869 100644 --- a/drivers/gnss/Kconfig +++ b/drivers/gnss/Kconfig @@ -54,4 +54,15 @@ config GNSS_UBX_SERIAL If unsure, say N. +config GNSS_USB + tristate "USB GNSS receiver support" + depends on USB + help + Say Y here if you have a GNSS receiver which uses a USB interface. + + To compile this driver as a module, choose M here: the module will + be called gnss-usb. + + If unsure, say N. + endif # GNSS diff --git a/drivers/gnss/Makefile b/drivers/gnss/Makefile index 451f11401ecc..bb2cbada3435 100644 --- a/drivers/gnss/Makefile +++ b/drivers/gnss/Makefile @@ -17,3 +17,6 @@ gnss-sirf-y := sirf.o obj-$(CONFIG_GNSS_UBX_SERIAL) += gnss-ubx.o gnss-ubx-y := ubx.o + +obj-$(CONFIG_GNSS_USB) += gnss-usb.o +gnss-usb-y := usb.o diff --git a/drivers/gnss/usb.c b/drivers/gnss/usb.c new file mode 100644 index 000000000000..fb1dd04fecb6 --- /dev/null +++ b/drivers/gnss/usb.c @@ -0,0 +1,213 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Generic USB GNSS receiver driver + * + * Copyright (C) 2021 Johan Hovold <johan@kernel.org> + */ + +#include <linux/errno.h> +#include <linux/gnss.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/usb.h> + +#define GNSS_USB_READ_BUF_LEN 512 +#define GNSS_USB_WRITE_TIMEOUT 1000 + +static const struct usb_device_id gnss_usb_id_table[] = { + { } +}; +MODULE_DEVICE_TABLE(usb, gnss_usb_id_table); + +struct gnss_usb { + struct usb_device *udev; + struct usb_interface *intf; + struct gnss_device *gdev; + struct urb *read_urb; + unsigned int write_pipe; +}; + +static void gnss_usb_rx_complete(struct urb *urb) +{ + struct gnss_usb *gusb = urb->context; + struct gnss_device *gdev = gusb->gdev; + int status = urb->status; + int len; + int ret; + + switch (status) { + case 0: + break; + case -ENOENT: + case -ECONNRESET: + case -ESHUTDOWN: + dev_dbg(&gdev->dev, "urb stopped: %d\n", status); + return; + case -EPIPE: + dev_err(&gdev->dev, "urb stopped: %d\n", status); + return; + default: + dev_dbg(&gdev->dev, "nonzero urb status: %d\n", status); + goto resubmit; + } + + len = urb->actual_length; + if (len == 0) + goto resubmit; + + ret = gnss_insert_raw(gdev, urb->transfer_buffer, len); + if (ret < len) + dev_dbg(&gdev->dev, "dropped %d bytes\n", len - ret); +resubmit: + ret = usb_submit_urb(urb, GFP_ATOMIC); + if (ret && ret != -EPERM && ret != -ENODEV) + dev_err(&gdev->dev, "failed to resubmit urb: %d\n", ret); +} + +static int gnss_usb_open(struct gnss_device *gdev) +{ + struct gnss_usb *gusb = gnss_get_drvdata(gdev); + int ret; + + ret = usb_submit_urb(gusb->read_urb, GFP_KERNEL); + if (ret) { + if (ret != -EPERM && ret != -ENODEV) + dev_err(&gdev->dev, "failed to submit urb: %d\n", ret); + return ret; + } + + return 0; +} + +static void gnss_usb_close(struct gnss_device *gdev) +{ + struct gnss_usb *gusb = gnss_get_drvdata(gdev); + + usb_kill_urb(gusb->read_urb); +} + +static int gnss_usb_write_raw(struct gnss_device *gdev, + const unsigned char *buf, size_t count) +{ + struct gnss_usb *gusb = gnss_get_drvdata(gdev); + void *tbuf; + int ret; + + tbuf = kmemdup(buf, count, GFP_KERNEL); + if (!tbuf) + return -ENOMEM; + + ret = usb_bulk_msg(gusb->udev, gusb->write_pipe, tbuf, count, NULL, + GNSS_USB_WRITE_TIMEOUT); + kfree(tbuf); + if (ret) + return ret; + + return count; +} + +static const struct gnss_operations gnss_usb_gnss_ops = { + .open = gnss_usb_open, + .close = gnss_usb_close, + .write_raw = gnss_usb_write_raw, +}; + +static int gnss_usb_probe(struct usb_interface *intf, const struct usb_device_id *id) +{ + struct usb_device *udev = interface_to_usbdev(intf); + struct usb_endpoint_descriptor *in, *out; + struct gnss_device *gdev; + struct gnss_usb *gusb; + struct urb *urb; + size_t buf_len; + void *buf; + int ret; + + ret = usb_find_common_endpoints(intf->cur_altsetting, &in, &out, NULL, + NULL); + if (ret) + return ret; + + gusb = kzalloc(sizeof(*gusb), GFP_KERNEL); + if (!gusb) + return -ENOMEM; + + gdev = gnss_allocate_device(&intf->dev); + if (!gdev) { + ret = -ENOMEM; + goto err_free_gusb; + } + + gdev->ops = &gnss_usb_gnss_ops; + gdev->type = GNSS_TYPE_NMEA; + gnss_set_drvdata(gdev, gusb); + + urb = usb_alloc_urb(0, GFP_KERNEL); + if (!urb) { + ret = -ENOMEM; + goto err_put_gdev; + } + + buf_len = max(usb_endpoint_maxp(in), GNSS_USB_READ_BUF_LEN); + + buf = kzalloc(buf_len, GFP_KERNEL); + if (!buf) { + ret = -ENOMEM; + goto err_free_urb; + } + + usb_fill_bulk_urb(urb, udev, + usb_rcvbulkpipe(udev, usb_endpoint_num(in)), + buf, buf_len, gnss_usb_rx_complete, gusb); + + gusb->intf = intf; + gusb->udev = udev; + gusb->gdev = gdev; + gusb->read_urb = urb; + gusb->write_pipe = usb_sndbulkpipe(udev, usb_endpoint_num(out)); + + ret = gnss_register_device(gdev); + if (ret) + goto err_free_buf; + + usb_set_intfdata(intf, gusb); + + return 0; + +err_free_buf: + kfree(buf); +err_free_urb: + usb_free_urb(urb); +err_put_gdev: + gnss_put_device(gdev); +err_free_gusb: + kfree(gusb); + + return ret; +} + +static void gnss_usb_disconnect(struct usb_interface *intf) +{ + struct gnss_usb *gusb = usb_get_intfdata(intf); + + gnss_deregister_device(gusb->gdev); + + kfree(gusb->read_urb->transfer_buffer); + usb_free_urb(gusb->read_urb); + gnss_put_device(gusb->gdev); + kfree(gusb); +} + +static struct usb_driver gnss_usb_driver = { + .name = "gnss-usb", + .probe = gnss_usb_probe, + .disconnect = gnss_usb_disconnect, + .id_table = gnss_usb_id_table, +}; +module_usb_driver(gnss_usb_driver); + +MODULE_AUTHOR("Johan Hovold <johan@kernel.org>"); +MODULE_DESCRIPTION("Generic USB GNSS receiver driver"); +MODULE_LICENSE("GPL v2"); |